Turning machine



April 13, 1943.

DE wl'r'r cLAusEN 2,316,405

TURNING MACHINE Filed June 5, 1940 5 Sheets-Sheet 2 April 13, 1943 A DE wlrT cLAusr-:N 2,316,405

v TURNING MACHINE Filed June 5. 1940 5 -sheetsfheet s I HL, 4 5. ?LL M rwval M 1 ,v I ,mTrmJn .JL/l- :Il IWVVWIJH Cawe/z DE wlrT CLAUSEN 2,316,405

April 13, 1943.

' TURNING MACHINE Filed June 5, 1940 5 sheets-sheet 4 DE wlTT cLAUsEN y April 13, 1943.

v TURNING MACHINE'.

Filed June 5, 1940 5 sheets-sheet 5 Patented Apr. 13, 1943 f angiot- TURNDIG MACHENE lle-Witt Clausen, Akron, Ohio, assigner to Lucien I. Yeomans, Incorporated, Chicago, Ill., a corporation of Illinois Application `lune 5, 1940, Serial No. 338,974

(Cl. ft2- 14) 12- claims.

This invention relates to turning machines and has more particular reference to the contour turning of metal bodies of circular cross section. A general aim of the invention is to-provide a new and improved former-controlled contour turning atachment for a machine of the above mentioned general type.

It is an object of the invention to provide a novel former-controlled contour turning machine wherein cutting tools oppositely disposed radially of a workpiece are separately controlled by cam followers disposed on the opposite sides of a former or template.

It is a further object of the invention to provide a machine of this type wherein the former is fixed in spaced parallel relation to the workpiece, each tool being connected with one of the followers for causing relative transaxial movement between the tool and the workpiece in conformity with the side of the former which is located relatively opposite to or in non-conforming relation to the side of said workpiece being engaged by the tool.

It is a further object of the invention tov provide a machine of this type wherein there is substantially no bending stress on either the former or workpiece during operation on a workpiece having a circular cross section, there being substantially equal and opposite compression on their opposite sides at all times.

vFurther objects and advantages will becomev Fig. 4 is a fragmentary horizontal section taken along th-e line 3 4 of Fig. 2 and looking downwardly. Fig. 5 is a somewhat diagrammatic plan view of a lmodiied form of the invention applied to aA conventional turning lathe.

Fig. 6 is a side elevation of the tool supporting means shown in Fig. 5.

Fig. '7 is a sectional View of the former-conf' trolied contour turning attachment shown in Fig. 5 and taken along line 1 1.

Fig. 8 is a sectional view taken along line 8 2! of Fig. 7.

Fig. 9 is a Vertical sectional View of said attachment taken along the line 9-9 of Fig. 5.

Fig. 10 is a detail sectional View of a cam follower and support taken along line Illl0 of Fig. l1 is a somewhat diagrammatic View of a conventional turret lathe equipped with a modined form of temer-controlled contouring at-l taohment.

While the invention is susceptible of various modiiications and alternative construction, I have shown in the drawings and will herein describein detail, the preferred embodiments, but it is to be understood that I do not thereby intend to' limit the invention to the specic forms disclosed, but intend to cover all modications and alternative constructions falling within the spirit and scope of the invention as expressed in the alp--l pended claims.

The present invention has application to any form yoi turning machine wherein a workpiece is turned down to any particular contour of circular cross section. Thus, for example, the invention has been illustrated and will hereinafter be described in connection with a turning machine of the type disclosed in the copendingjoint application of Lucien I. Yeomans and DeWitt Clausen, Serial No. 337,760 filed May 29, 1940, now Patent 2,283,578 of June 30, 1942, wherein the workpiece is causedv to rotate and reciprocate on a traveling carriage relative to a stationary toolhead (Figs. 1, 2, 3 and'I 4). A modied form of the invention has also been illustrated and will be described in connection with a conventional turning lathe where# in the tool isv caused to reciprocate relative to a; workpiece mounted for rotation on the machine base (Figs. 5, 6, 7, 8, 9 'and 10) and thirdly, as` applied to a conventional turret lathe (Fig. 11')-. It is to be understood, however, that, broadly, the concept of the present invention is applicable toany type of turning machine.

The turning machine disclosed in Figs. 1, 2,A 3f' and Il, tor purposes of illustrating one applica' tion oi the present invention, will be described only briefly, reference being made to the aforementioned joint application of Yeomans and Clausen for details which form no part of the present invention. Referring to Fig. 1 in particular, the maclnne comprises generally an elongated box frame 2o supported by pedestals 2i which may be suitably secured thereto in any desired manner. is slidably supported for longitudinally traversiing the frame along one side 23 thereof. To this end spaced parallel guideways 24 are supported A work supporting carriage 22- one above the other in brackets projecting from the side of the machine. The carriage being of a substantially rectangular open form is supported at its four corners on said guideways by suitable bearings 26. The carriage is equipped with a headstock 21 and a tailstock 28 in which spindles 29 and 30, respectively, are suitably journaled for rotatably supporting a workpiece 32 on centers 33 and 34, respectively, with its axis substantially paralleling the path of' travel of the carriage. The headstock spindle is provided with suitable driving means, indicated at 3|, for rotating the workpiece. Hydraulic means, indicated in part at 35, are provided for actuating the tailstock spindle for the purpose of clamping the workpiece between centers 33 and 34 of the headstock and tailstock, respectively. The headstock or live spindle 2S is suitably driven by means (not shown) connected through a gear box 36 with a drive shaft 31. Suitable drive means, generally indicated at 38, is provided for traversing the carriage.

A spindle clutch control lever 38' is mounted on the base for manual control of the headstock spindle drive. A feed clutch control and rapid traverse reverse clutch control lever 48 is suitably positioned on the top of the frame for manually controlling the carriage feed and rapid tra,- verse reverse. Automatic means, generally indicated at 43, for stopping the carriage at the end of a` feed stroke and again at the end of a rapid traverse reverse stroke, is positioned for engagement by a lug 44 projecting upwardly from the carriage. A handwheel 45, fixed on a shaft 46 transversely journaled in the carriage, is provided for manually positioning the carriage relative to the machine base. For a more detailed understanding of the spindle and carriage drive and control mechanisms, reference may be had to the aforesaid Yeomans and Clausen application.

Means-are provided for mounting cutting tools peripherally about the workpiece for sliding4 movement radially thereof during rotationand longitudinal feed. To this end, a tool pedestal or knee 41 is rigidly secured to the side |5 of the machine and projects laterally therefrom into the open central portion of the carriage. The knee 41 is formed with a central aperture 49 through which the workpiece 32' is adapted to reciprocate and rotate between the headstock and tailstock on the carriage. A toolhead 58 having a corresponding central aperture 53 is bolted, as at 54, to a machined faceI 55 of the knee and centered thereon by an annular collar 56 formed on the toolhead for registration with a complementary seat 51 formed in the face of the knee.

In the present instance, a pair of cutting tools 58 and 59 are oppositely disposed relative to the workpiece, one above and one below, and are mounted for sliding movement on the toolhead transaxially of the workpiece. To this end, a pair of tool slidesV |50A and 5| provided with dovetail slots 63 and 64 for cooperation with complementary dovetails 85 and 85 formed on the toolhead are mounted thereon for vertical sliding movement, one above the workpiece and one below. Each slide carries a tool support 61, pivoted thereon, as at 68, for substantially radial tool adjustment by adjusting screw 59 and rmly secured to the slide by a pair of lock bolts .10 and 1| screw threaded therein through slots 12 and 13 in the tool support. Each tool is received in a pocket 15 where it is adjustable tangentially of the workpiece by an adjusting screw 16 screw threaded in the support and which serves also to prevent endwise movement of the tool incident to rotation of the workpiece.

One important feature of the present invention is to provide cam or former means xed in spaced relation to the workpiece and contoured symmetrically for effecting synchronous transaxial movement of the cutting tools as an incident to relative longitudinal feed movement between the workpiece and former cn the one hand and the tool support on the other. Thus in the present instance, the former or template, generally indicated at B, is fixed on the carriage for reciprocatory movement therewith in spaced parallel relation. to the workpiece. Brackets 8| and 82`, secured to' one of the longitudinal side members of the carriage, are adapted to receive and rigidly secure the ends 83 and 84 of said former to the carriage. The former, as illustrated in the present instance, is contoured reversely to the desired workpiece contour and is preferably of circular cross section throughout, providing at least two opposite symmetrical sides 85 and 86. A pair of roller followers 81 and 88 are positioned on said opposite sides for movement transversely of the former during axial reciprocatory movement thereof.

Means are provided for rigidly connecting each of said toolsv with one of said followers for causing relative transaxial movement between the tool and the workpiece in conformity with the side of the former which is located relatively opposite or in non-conforming relation to the side of said workpiece being engaged by the tool. Thus, as viewed in Figs. 2 and 3, the bottom or adjacent follower 88 is journaled, as at 89, in the tool slide 6|) which carries the top or adjacent tool 58 while the top or remote follower 81 controls the bottom or remote tool 59. A pair of spaced tension rods 90 and 9|, straddling the former, are secured to a yoke 94 in which the remote follower 81 is journaled, as at 95. The rods 98 and 9| extend slidably through the top and bottom tool slides to support the latter for movement in conformity with the top roller follower 81. A coil spring 96, seated in a pocket 91 in the toolhead and abutting a plate 98 bolted, as at 99, to the under side of the bottom tool slide,

l yieldably maintains a constant following engagement between the top follower and the former and prevents gouging of the workpiece by the bottom tool. Similarly a coil spring |88, seated in a pocket |0| in the toolhead, abuts an extended portion |02 of the top tool slide to yeldably maintain a constant following engagement between the bottom follower 88 and the former and prevent gouging of the workpiece by the top tool.

Utilizing a reverse former of the type having a circular cross Section throughout, as illustrated in Figs. 1 to 4, inclusive, I have provided a novel method for turning a workpiece to duplicate a model thereof. Heretofore, the production of reverse cams and formers has been a laborious and time consuming task requiring extreme accuracy in the plotting of coordinates and in the execution of such coordinates to produce a nished reverse former. The present method is designed to eliminate these diculties and provide a simple and expeditious process for producing a reverse former of circular cross section throughout from a model of the work to be produced.

A model of the work to be produced is positioned in a reverse contour turning machine, of the general type heretofore described, for use as a master former. A workpiece is positioned between the headstock and tailstock and is turned under the influence of the model to produce a former which is the reverse or complement of said model. This reversal is due to the fact that, during the relative movement between the model and the workpiece on the one hand and the cutting tool on the other, transaxial movement between the cutting tool and the workpiece is effected in conformity with the side of the model which is located relatively opposite to the side of the workpiece being engaged by the tool. The model is then replaced with the reverse former thus produced and a workpiece which is an exact duplicate of the model is produced under the influence of such a reverse former. This method results in extreme accuracy and exactness for the reason that the steps of producing the reverse former and subsequently producing a workpiece from such former are reversed, so that any in-l accuracies in the one step are compensated and eliminated in the succeeding step.

Figs. to 10, inclusive, disclose a modiiied form of the invention which is particularly well adapted for turning artillery shells, such as that illustrated at |93, which are usually provided with a straight cylindrical section |94 and a nose section |65 contoured to ogival or other rounded form. For turning the straight cylindrical section |64, a pair of cutting tools |96 and |61 are oppositely fixed in position relative to the axis of the workpiece, whereas, in the turning of the nose portion, a pair of cutting tools |08 and |09 are oppositely positioned relative to the axis of the workpiece for movement transaxially thereof under the control of a former.

The modified form disclosed is illustrated in connection with a conventional turning lathe shown in somewhat diagrammatic form in Fig. 5. The shell |63 may be supported in any suitable fashion for rotation between headstock and tailstock centers H6 and respectively, supported on a machine bed HZ. A tool carriage 3 is slidably supported on cylindrical Ways 4 and I |5 ou the machine bed for longitudinal reciprocation axially of the workpiece. Two pairs of tool supports are mounted on the carriage, one pair, denominated |29 and |2|, supporting the tools |96 and |91, respectively, and the other pair denominated |22 and |23 supporting tools |08 and |99, respectively. The tool supports |29 and |2| are mounted on the carriage for preliminary adjusting movement individually longitudinally and synchronously radially of the workpiece.' Tool support |2| is also preliminarily radially adjustable individually rela-tive to the workpiece and to the support |20.

To accomplish these adjustments, a pair ofV slides |24 and |25 are mounted on slideways |26 which extend across the carriage. The slides carry screw threaded sleeves |21 and |28, respectively, bolted thereto as at |29 and |36 for projection downwardly into a recess |33 formed between the slideways. An actuating screw |34,- having oppositely threaded screw sections |35 and |36, is journaled as at |31 transversely in the carriage and its sections |35 and |36 are received in the sleeves |21 and |28, respectively. Actuation of the screw by a handwheel |33 at the front' of the carriage, advances or retracts the slides synchronously relative to the axis of the workpiece. The slides |24 and |25 carry actuating screws |39 andl |46, respectively, journaled therein for cooperation with tapped projections |43 and |44; the former projection is rigid with the tool support |20 which has a sliding dovetail relation with the slide |24 and the latter is rigid with an intermediate slide |48 which has a sliding dovetail relation with the slide |25. Separate adjustment of the actuating screws |39 andV |46 effects movement of the tool supports longitudinally of the workpiece. The intermediate slide |48 is dovetailed as at |49 for cooperation with a dovetail recess |59 in the tool support |2| and carries an actuating screw |5| which is received in a tapped projection |52 in said tool support. Actuation of the screw |5| adjusts tool support |2| radially of the workpiece and relative to its opposed tool support 26. Y

The contour turning tools |96 and |69 are each adjustable preliminary to the turning operation for separate movement longitudinally of the workpiece and for the adjustment of tool |09 radially of the workpiece and relative to the tool |08. A pair of slides |53 and |54 are mounted on slideways |55 extending across the carriage. Slide |53 carries the tool support |22, the parts being slidably dovetailed, as indicated at |56.' An actuating screw |51, journaled in the slide |53,

- has a screw threaded connection |58 with'the support |22 for adjustment of tool |98 longitudinally of the workpiece. Slide |54 carries an iniermediate slide |59 which in turn carries the tool support |23, the parts being slidably dovetailed as indicated at |60 and |6|. An actuating screw |62, journaled in the slide |54, has a screw threaded connection |63 with intermediate slide |59 for adjustment of tool |69 longitudinally of the workpiece and an actuating screw |64, journaled in the intermediate slide |59 has a screw threaded connection with the tool support |23 for adjustment of tool |69 radially of the workpiece and relative to its opposed tool |98. A former |19, having opposite symmetrical sides |1| andv |12, is rigidly supported atl its ends |13 and |14 on brackets |15 and |16 secured to the machine base. The former is disposed in spaced parallel relation to the workpiece and is contoured reversely to the workpiece similarly to the former 69 previously described. A pair of roller followers |11 and |18 are positioned on said opposite sides for movement transversely of the former during relative axial movement between tne workpiece and the cutting tools.

Means is provided for connecting each of the oppositely disposed tools |93 and |69 with one of said followers for causing relative transaxial movement between the tool and the workpiece in conformity with the side of the former which is located relatively opposite to the side of 'said workpiece being engaged by the tool. The remote follower |11 is journaled in a support |19 slidable in the carriage (see Fig. 10) and which is connected through spaced tension rods |89 and with a sleeve $82, bolted as at |83, to the slide |54 which carries the remote tool |99. The adjacent follower |18 is similarly journaled in a sliding support |34 which is connected with the means supporting the adjacent tool |66. This latter connection is adjustable for positioning the adjacent tool relative to its follower and is effected lby means of an actuating screw journeled in the follower support |84 and having a screw threaded relation with a sleeve |86, bolted, as at |81, on the adjacent tool slide |53. The actuating screw |65 is also journaled, as indicated at |66, for extension from the front of the carriage where it is actuated by a handwheel |69. A coil spring |96 extends between the sleeves |32 and |86 on the tool slides |53 and.

|54 for yieldably maintaining a constant following engagement between the followers and the former and also serving to prevent gouging of the workpiece by the tools.

It will be apparent that the tools |08 and |09 are controlled by the former for contouring the ogival portion |05 of the shell while the tools |06 and |01 are rigid with the carriage during the cutting operation to form the straight cylindrical section |04.

Another modification of the invention is disclosed in Fig. ll, wherein a conventional turret lathe construction is shown in somewhat diagrammatic form. The machine comprises generally a base |95 upon which a revolvable turret |05, having a plurality of forming tools |01, |98 and |99 spaced peripherally thereof, is mounted for longitudinal feed movement. A workpiece 200 is mounted for rotation on the machine base on a chuck, generally indicated at 20|, and 13ositioned for successive engagement by the forming tools as they are indexed on the turret.

The turret is indexed, in the position shown in Fig, 1l, to position a contour turning attachment similar to that described with reference to Figs. l to 4, inclusive, for engagement with the workpiece 200. The attachment comprises a tool support 202 bolted, as at 203, to a peripheral face of the turret and supporting a toolhead 204, bolted thereto as at 205. The toolhead carries a pair of oppositely disposed tool slides 206 and 201 vertically slidable thereon. These carry toolliolders 208 and 209 which position a pair of cutting tools 2|0 and 2|I in oppositely disposed relation to the workpiece. A pair of roller followers 2|2 and 2|3 are connected, respectively, with the bottom and top tool slides 201 and 205 and are adapted for following engagement with a former 22| fixed on the machine base in spaced parallel relation to the workpiece. The top or remote follower 2|2 is journaled in a follower support 2|4 rigid with a pair of spaced tension members 2|5 and 2|0 which straddle the former and the workpiece for sliding engagement with the top or adjacent tool slide 206 and for connection with the bottom or remote tool slide 201. A coil spring 2|1, seated in the toolhead, abuts against a plate 2 |8 bolted to the underside of the bottom tool slide 201, for yieldably maintaining a constant following engagement between the remote follower and the former. The bottom or adjacent follower 2 |3 is journaled in the top tool slide 206 and is similarly yieldably urged into constant following engagement with the former by a coil spring 219 seated in the toolhead and abutting a projection 220 formed ori said top tool slide 206.

As the turret is fed longitudinally of the former and workpiece while the latter is rotated, the followers engage the opposed sides of a conical end portion 222 of the former 22| and are spread apart to initiate their following relation with the former. When the tools reach the workpiece the followers are positioned to control their transaxial cutting movement in accordance with the symmetrical opposite sides of the reverse former.

I claim as my invention:

l. A turning machine having, in combination, means for rotating a workpiece having axially spaced areas to be turned to different diameters, a symmetrical reverse former fixed in spaced parallel relation to said workpiece, a support relatively movable axially of said workpiece and said former, two followers mounted on said supfor advancement and retraction relative to the axis of the work, each tool being supported for joint movement with one of said followers, said tools and said followers being in substantial alinement.

2. A turning machine comprising, in combination, means for supporting a workpiece, means for supporting a pair of cutting tools at diametrically opposite sides of said workpiece, means for eiecting relative rotation and longitudinal reciprocation between said workpiece and said cutting tools, and means for advancing and retracting said tools in synchronism relative to the axis of said workpiece, said last mentioned means including a former having opposite symmetrical sides contoured reversely to the desired workpiece contour and xed in spaced parallel relation to said workpiece, and a pair of followers each paired with one of said tools and each coacting with one of said opposite symmetrical sides for synchronous movement transversely of said former, said tools and said followers being in substantial alinement.

3. A turning machine comprising, in combination, means for supporting a workpiece, means for supporting a pair of cutting tools at diametrically opposite sides of said workpiece, means for effecting relative rotation and longitudinal reciprocation between said workpiece and said cutting tools, and means for advancing and retracting said tools in synchronism relative to the axis of said workpiece, said last mentioned means including a former fixed in spaced parallel relation with respect to said workpiece and having a side remote from said workpiece symmetrical with an opposite side near said workpiece, a remote side follower connected with the tool on the remote side of said workpiece, and a near side follower connected with the tool on the near side of said workpiece.

4. In a turning machine for effecting relative rotation and longitudinal feed between a tool support and a workpiece having axially spaced areas to be turned to different diameters, the combination of a reverse former of circular cross section fixed in spaced parallel relation to said workpiece, a pair of cutting tools oppositely disposed relative to the diameter of said workpiece, each mounted on said tool support for movement transaxially of said workpiece, and a pair of followers oppositely disposed with respect to the diameter of said former, said diameter being substantially in a straight line and each of said followers being separately connected with one of said tools for effecting transaxial movement of each cutting tool relative to the workpiece in conformity with the side of said former which is located relatively opposite to the side of said workpiece being engaged by the tool.

5. In a turning machine for effecting relative rotation and longitudinal feed between a tool support and a workpiece having axially spaced areas to be turned to different diameters, the combination of a reverse former having contoured cam faces on its opposite sides and fixed in spaced parallel relation to said workpiece, a pair of former followers coacting with said cam faces and adapted for separate movement transversely of said former, a pair of tools oppositely disposed relative to said workpiece, each mounted on said tool support for movement transaxially of said workpiece, and means connecting each of said followers with one of said tools for effecting relative transaxial movement between each tool and the workpiece in conformity with the side of said former which is located relatively opposite to the side of said workpiece being engaged by the tool.

6. A turning machine comprising, in combination, a work support, a tool support, a former having a contour the reverse of that of the workpiece to be turned, means for rotating said work support, means for effecting relative feeding movement between said tool support on the one hand and said work support and former on the other, a pair of tools movably mounted on said tool support in position to engage the workpiece at circumferentially spaced points thereon, a pair of follower elements movably mounted to engage said former at corresponding circumferentially spaced points thereon, said tools and said followers being in substantial alinement, means connecting the follower element nearer to the workpiece to the tool nearer to the former, and means connecting the follower element farther from the workpiece to the tool farther from the former, to effect synchronous approach and recession of the tools transaxially of the workpiece in conformity with the contour of said former during the aforesaid relative feeding movement.

7. A turret lathe comprising, in combination, means for rotatably supporting a workpiece, a reverse former having opposite symmetrical sides fixed in spaced parallel relation to said workpiece, a revolvable lathe turret having a plurality of tools mounted for radial extension peripherally thereof, one of said tools including a toolhead, a pair of followers separately movable on said toolhead transversely of said former for coaction with said opposite sides when said turret is positioned for utilizing said one tool, a pair of cutting tools on said tool head each connected with one of said followers and adapted for synchronous radial advancement and retraction relative to and from diametrically opposite sides of the axis of said workpiece under the inuence of said former, said tools and said followers being in substantial alinement, and means for effecting relative longitudinal feed between said workpiece and former on the one hand and said turret on the other.

8. A turret lathe comprising, in combination, means for rotatably supporting a workpiece, a former xed in spaced parallel relation to said workpiece and having a side remote from said workpiece symmetrical with an opposite side near said workpiece, a lathe turret having a plurality of tools mounted thereon, one of said tools including a toolhead, a pair of followers each cooperating with one of said sides, separate means in support of each follower and freely movable on said toolhead transversely of said workpiece and said former when said turret is indexed for utilizing said one tool, a pair of cutting tools on said tool head each connected with one of said followers and adapted for synchronous radial advancement and retraction relative to and from diametrically opposite sides of the axis of said workpiece in conformity with the side of said former which is located relatively opposite to the side of said workpiece being engaged by the tool, and means for effecting relative longitudinal feed between said workpiece and said turret.

9. A turning machine comprising, in combination, a base, a carriage mounted for longitudinal traverse on said base, means on said carriage for rotatably supporting a circular workpiece with its axis parallel to the path of traverse of said workpiece, a tool support on said base and disposed adjacent said path, a reverse former of circular cross section fixed on said carriage in spaced parallel relation t0 said workpiece, a pair of followers oppositely disposed with respect to the diameter of said former, a pair of cutting tools oppositely disposed with respect to the diameter of said workpiece, said diameters being in substantially a straight line, and means on said toolhead for connecting each tool with one of said followers for equal synchronous radial advancement and retraction of said tools relative to the axis of said workpiece upon traversing movement of said carriage.

10. A lathe comprising, in combination, a base, a tool carriage mounted for traversing movement on said base, means on said base for rotatably supporting a workpiece having axially spaced areas to be turned to different diameters, a reverse former having opposite symmetrical sides xed on said base in spaced parallel relation to said workpiece, a pair of followers each freely movable on said toolcarriage transversely of said former for coaction with said opposite sides, and a pair of cutting tools each connected with one of said followers and adapted for separate synchronous radial advancement and retraction relative to the axis of said workpiece under the influence of said followers, the movement of each tool being in conformity with the side of said former which is located relatively opposite to the side of said workpiece being engaged by the tool.

11. In a turning machine wherein relative rotational and longitudinal feed movement is effected between a tool support and a circular workpiece to be turned, a contouring attachment comprising, in combination, a former paralleling said workpiece, followers coacting with directly opposite sides of said former, tools coacting with diametrically opposed sides of said workpiece, said tools and said followers being substantially in alinement, and means connecting each tool with a follower, the opposite disposition of the tools and followers relative to the workpiece and former respectively being such that each is subjected to equal and opposite bending stresses.

12. In a turning machine wherein relative rotational and longitudinal feed movement is effected between a tool support and a circular workpiece having axially spaced areas to be turned to different diameters, the combination of a reverse former fixed in spaced parallel relation to said workpiece and having opposite symmetrical sides, a pair of cutting tools on said support oppositely disposed diametrically of the axis of said workpiece, and a pair of former followers each fixed relative to one of said tools, said tools and said followers being substantially in alinement, the relationship being such that equal and opposite cutting force is exerted through the workpiece to each tool causing equal and opposite follower force on the former whereby neither workpiece nor former are subjected to bending stress.

DE WITT CLAUSEN. 

